2 * Copyright (c) 2016 Konrad Witaszczyk <def@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/types.h>
31 #include <sys/capsicum.h>
32 #include <sys/endian.h>
33 #include <sys/kerneldump.h>
35 #include <sys/sysctl.h>
45 #include <openssl/evp.h>
46 #include <openssl/pem.h>
47 #include <openssl/rsa.h>
48 #include <openssl/engine.h>
52 #define DECRYPTCORE_CRASHDIR "/var/crash"
59 "usage: decryptcore [-Lv] -p privatekeyfile -k keyfile -e encryptedcore -c core\n"
60 " decryptcore [-Lv] [-d crashdir] -p privatekeyfile -n dumpnr");
64 wait_for_process(pid_t pid)
68 if (waitpid(pid, &status, WUNTRACED | WEXITED) == -1) {
69 pjdlog_errno(LOG_ERR, "Unable to wait for a child process");
73 if (WIFEXITED(status))
74 return (WEXITSTATUS(status));
79 static struct kerneldumpkey *
82 struct kerneldumpkey *kdk;
86 PJDLOG_ASSERT(kfd >= 0);
88 kdksize = sizeof(*kdk);
89 kdk = calloc(1, kdksize);
91 pjdlog_errno(LOG_ERR, "Unable to allocate kernel dump key");
95 size = read(kfd, kdk, kdksize);
96 if (size == (ssize_t)kdksize) {
97 kdk->kdk_encryptedkeysize = dtoh32(kdk->kdk_encryptedkeysize);
98 kdksize += (size_t)kdk->kdk_encryptedkeysize;
99 kdk = realloc(kdk, kdksize);
101 pjdlog_errno(LOG_ERR, "Unable to reallocate kernel dump key");
104 size += read(kfd, &kdk->kdk_encryptedkey,
105 kdk->kdk_encryptedkeysize);
107 if (size != (ssize_t)kdksize) {
108 pjdlog_errno(LOG_ERR, "Unable to read key");
119 decrypt(const char *privkeyfile, const char *keyfile, const char *input,
122 uint8_t buf[KERNELDUMP_BUFFER_SIZE], key[KERNELDUMP_KEY_MAX_SIZE];
124 const EVP_CIPHER *cipher;
126 struct kerneldumpkey *kdk;
128 int ifd, kfd, ofd, olen, privkeysize;
132 PJDLOG_ASSERT(privkeyfile != NULL);
133 PJDLOG_ASSERT(keyfile != NULL);
134 PJDLOG_ASSERT(input != NULL);
135 PJDLOG_ASSERT(output != NULL);
140 * Decrypt a core dump in a child process so we can unlink a partially
141 * decrypted core if the child process fails.
145 pjdlog_errno(LOG_ERR, "Unable to create child process");
150 return (wait_for_process(pid) == 0);
152 kfd = open(keyfile, O_RDONLY);
154 pjdlog_errno(LOG_ERR, "Unable to open %s", keyfile);
157 ifd = open(input, O_RDONLY);
159 pjdlog_errno(LOG_ERR, "Unable to open %s", input);
162 ofd = open(output, O_WRONLY | O_CREAT | O_TRUNC, 0600);
164 pjdlog_errno(LOG_ERR, "Unable to open %s", output);
167 fp = fopen(privkeyfile, "r");
169 pjdlog_errno(LOG_ERR, "Unable to open %s", privkeyfile);
173 if (cap_enter() < 0 && errno != ENOSYS) {
174 pjdlog_errno(LOG_ERR, "Unable to enter capability mode");
179 if (privkey == NULL) {
180 pjdlog_error("Unable to allocate an RSA structure: %s",
181 ERR_error_string(ERR_get_error(), NULL));
184 EVP_CIPHER_CTX_init(&ctx);
191 privkey = PEM_read_RSAPrivateKey(fp, &privkey, NULL, NULL);
193 if (privkey == NULL) {
194 pjdlog_error("Unable to read data from %s.", privkeyfile);
198 privkeysize = RSA_size(privkey);
199 if (privkeysize != (int)kdk->kdk_encryptedkeysize) {
200 pjdlog_error("RSA modulus size mismatch: equals %db and should be %ub.",
201 8 * privkeysize, 8 * kdk->kdk_encryptedkeysize);
205 switch (kdk->kdk_encryption) {
206 case KERNELDUMP_ENC_AES_256_CBC:
207 cipher = EVP_aes_256_cbc();
210 pjdlog_error("Invalid encryption algorithm.");
214 if (RSA_private_decrypt(kdk->kdk_encryptedkeysize,
215 kdk->kdk_encryptedkey, key, privkey,
216 RSA_PKCS1_PADDING) != sizeof(key)) {
217 pjdlog_error("Unable to decrypt key: %s",
218 ERR_error_string(ERR_get_error(), NULL));
224 EVP_DecryptInit_ex(&ctx, cipher, NULL, key, kdk->kdk_iv);
225 EVP_CIPHER_CTX_set_padding(&ctx, 0);
227 explicit_bzero(key, sizeof(key));
230 bytes = read(ifd, buf, sizeof(buf));
232 pjdlog_errno(LOG_ERR, "Unable to read data from %s",
235 } else if (bytes == 0) {
240 if (EVP_DecryptUpdate(&ctx, buf, &olen, buf,
242 pjdlog_error("Unable to decrypt core.");
246 if (EVP_DecryptFinal_ex(&ctx, buf, &olen) == 0) {
247 pjdlog_error("Unable to decrypt core.");
255 if (write(ofd, buf, olen) != olen) {
256 pjdlog_errno(LOG_ERR, "Unable to write data to %s",
262 explicit_bzero(buf, sizeof(buf));
263 EVP_CIPHER_CTX_cleanup(&ctx);
266 explicit_bzero(key, sizeof(key));
267 explicit_bzero(buf, sizeof(buf));
269 EVP_CIPHER_CTX_cleanup(&ctx);
274 main(int argc, char **argv)
276 char core[PATH_MAX], encryptedcore[PATH_MAX], keyfile[PATH_MAX];
278 const char *crashdir, *dumpnr, *privatekey;
283 pjdlog_init(PJDLOG_MODE_STD);
284 pjdlog_prefix_set("(decryptcore) ");
290 *encryptedcore = '\0';
294 while ((ch = getopt(argc, argv, "Lc:d:e:k:n:p:v")) != -1) {
300 strncpy(core, optarg, sizeof(core));
306 strncpy(encryptedcore, optarg, sizeof(encryptedcore));
309 strncpy(keyfile, optarg, sizeof(keyfile));
330 /* Verify mutually exclusive options. */
331 if ((crashdir != NULL || dumpnr != NULL) &&
332 (*keyfile != '\0' || *encryptedcore != '\0' || *core != '\0')) {
337 * Set key, encryptedcore and core file names using crashdir and dumpnr.
339 if (dumpnr != NULL) {
340 for (ii = 0; ii < strnlen(dumpnr, PATH_MAX); ii++) {
341 if (isdigit((int)dumpnr[ii]) == 0)
345 if (crashdir == NULL)
346 crashdir = DECRYPTCORE_CRASHDIR;
347 PJDLOG_VERIFY(snprintf(keyfile, sizeof(keyfile),
348 "%s/key.%s", crashdir, dumpnr) > 0);
349 PJDLOG_VERIFY(snprintf(core, sizeof(core),
350 "%s/vmcore.%s", crashdir, dumpnr) > 0);
351 PJDLOG_VERIFY(snprintf(encryptedcore, sizeof(encryptedcore),
352 "%s/vmcore_encrypted.%s", crashdir, dumpnr) > 0);
355 if (privatekey == NULL || *keyfile == '\0' || *encryptedcore == '\0' ||
361 pjdlog_mode_set(PJDLOG_MODE_SYSLOG);
362 pjdlog_debug_set(debug);
364 if (!decrypt(privatekey, keyfile, encryptedcore, core)) {
365 if (stat(core, &sb) == 0 && unlink(core) != 0)
366 pjdlog_exit(1, "Unable to remove core");